The Microbial Induced Calcite Precipitation (MICP) technique is nowadays a promising sustainable technology in the fields of geotechnical engineering and ground improvement. This study investigates the use of fly ash in the MICP process to develop a composite liner material. In this study, Class-F fly ash is used to examine the potential of MICP technique to improve its strength behavior. The MICP process involves the use of urease-producing bacteria, specifically Bacillus sp. (SP77), which facilitates calcite precipitation through the hydrolysis of urea in a calcium-rich environment. This precipitate calcite mineral acts as a binding agent, plugging the pores and enhancing the overall strength and stability of the liner material through biomineralization and biologging. The MICP-treated fly ash liner material was then used in a geotechnical test to assess its properties and ensure compliance with the design parameters of landfill liner materials. Compressive strength was assessed after 7, 14, and 21 days of MICP treatment. Calcite mineral formation was confirmed through the measurement of calcite through the calcimeter. This study revealed a significant increase in strength with the prolonged treatment cycle due to the plugging of pores with calcite and interparticle attachment by calcite bonding.